Flexible skirts for gas-cushion supported equipment

ABSTRACT

The invention relates to a flexible skirt for use on craft vehicles or devices which can be supported on a gas cushion, the skirt serving to prevent an escape of gas from the gas cushion to the atmosphere and comprising a plurality of juxtaposed segments which in use are downwardly extending and can seal against one another, each segment being U-shaped in transverse cross-section to form two side walls which gradually decrease in depth from their upper end towards their bottom end and the bottom edge or tip of each segment is disposed in a plane which is horizontal or at an angle to the horizontal less than the curved front edge of the segment.

United States Patent Hopkins et a1.

FLEXIBLE SKIRTS FOR GAS-CUSHION SUPPORTED EQUIPMENT Inventors: Leslie A. Hopkins; Robert R.

Henvest, both of Southampton, England Assignee: Air Cushion Equipment Limited,

Southampton, Hampshire, England Filed: Apr. 22, 1971 Appl. No.: 136,533

Foreign Application Priority Data Apr. 23, 1970 Great Britain 19,535/70 References Cited UNITED STATES PATENTS l/l969 Bliss 180/119 8/1970 Pinder 180/127 3,395,772 8/1968 Francis 180/127 FOREIGN PATENTS OR APPLICATIONS 1,187,476 4/1970 Great Britain 180/127 Primary ExaminerGerald M. Forlenza Assistant Examiner-D. W. Keen Attorney-Fleit, Gipple & Jacobson 57 ABSTRACT The invention relates to a flexible skirt for use on craft vehicles or devices which can be supported on a gas cushion, the skirt serving to prevent an escape of gas from the gas cushion to the atmosphere and comprising a plurality of juxtaposed segments which in use are downwardly extending and can seal against one another, each segment being U-shaped in transverse cross-section to form two side walls which gradually decrease in depth from their upper end towards their bottom end and the bottom edge or tip of each segment is disposed in a plane which is horizontal or at an angle to the horizontal less than the curved front edge of the segment.

' 10 Claims, 7 Drawing Figures Patented Aug. 14, 1913 3,752,253

2 Shouts-Sheet 1 Patented Aug. 14, 1973 3,752,253

2 Shoots-Sheet 2 BACKGROUND OF THE INVENTION It is known to have flexible sealing skirts for gas cushion supported craft, vehicles or devices which comprise a plurality of juxtaposed downwardly extending segments which, in use, seal one against the other and which are U-shaped in transverse cross-section and gradually taper from their upper end towards their lower end so that in side elevation they terminate at their lower end in a point. A disadvantage of such segments is that in moving the craft, vehicle or device on the gas cushion, the tips or bottom region of the segments of the skirt tend to deflect sideways resulting in the bottom end of the tip or bottom region extending outside the side wall of the segment and providing a leakage path for the gas providing the gas cushion.

SUMMARY OF THE INVENTION One object of the present invention is to provide an improved flexible skirt for use with craft, vehicles or devices which can be supported on a gas cushion, in which the tip portion of each segment of the skirt cannot deflect outside the side wall of the segment.

Another object of the present invention is to provide an improved flexible skirt in which the segments will seal against each other more quickly than known flexible skirt constructions, upon initial formation of the gas cushion.

According to the present invention there is provided a flexible segmented sealing skirt for use on apparatus which can be supported on a gas cushion, comprising a plurality of juxtaposed segments which in use are vertically extending and seal one against another, each segment being substantially U-shaped in transverse horizontal cross-section to provide a curved front wall and two side wall members, said side wall members having an upper end and a bottom end and each tapering from their upper end to their bottom end, the bottom end of each segment being provided with a bottom wall member lying in a plane which, when the skirt is in use, horizontal or lies at an angle to the horizontal which is less than the curved front wall of the segment.

BRIEF DESCRIPTION OF DRAWINGS To the accomplishment of the foregoing and related ends, the invention then comprises the features hereafter fully described and particularly pointed out in the claims, the following description and annexed drawings setting forth in detail certain illustrative embodiments of the ivention, these being indicative, however, of but ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a diagrammatic perspective view of a gas cushion lifting pad provided with a sealing skirt according to the present invention;

FIG. 2 is a perspective view of one embodiment of a segment of the flexible sealing skirt;

FIG. 3 is a perspective view of a second embodiment of a segment of the flexible sealing skirt;

FIG. 4 is a view of the segment taken in the direction of arrow 4 indicated on FIG. 3;

FIG. 5 is a longitudinal section through a third embodiment of a segment of the flexible sealing skirt;

2 FIG. 6 is a section taken along the line 6-6 indicated on FIG. 5; and

FIG. 7 is a longitudinal section through a fourth emblodiment of a segment of the flexible sealing skirt.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pad shown in FIG. 1 comprises an upper wall 10 around the periphery of which is attached a sealing skirt 11 comprising a plurality of juxtaposed vertically 'extending segments 12 which are formed of a flexible material and are substantially U-shaped in transverse horizontal cross-section. The upper edges of the segments 12 are secured to the underside of the upper wall 10 which itself may be formed of a flexible material. The space formed between the surface contacted by the segments 12 and the underside of the upper wall 10 and enclosed within the skirt ll constitutes a plenum chamber 13 to which a gas, such as air, under pressure is supplied through a duct 14 to form a gas cushion for supporting any load applied to the top surface of the upper wall 10. When compressed gas is fed to the plenum chamber 13 the sides of adjacent segments 12 seal against each other to form a gas seal.

In the embodiment shown in FIG. 2 each U-shaped segment 12 has side walls 15 which gradually taper from the upper end to the bottomend, the bottom edge 15a of each wall 15 lying in a plane which, when the skirt is in use, is horizontal. The bottom edges 15a are connected together by a bottom wall portion 16 which is formed by inwardly bending the bottom end portion of the curved front wall 17 of the segment 12. The bottom wall portion 16 is, in use, maintained within the side walls 15 by a tensioning device in the form of a strap, cord, wire or line 18 which extends from the bottom wall portion 16 and is connected at its other end to the upper wall 10. Where no upper wall 10 is provided, then the strap, cord, wire or line 18 is connected to a fixed part of the craft, vehicle or device to which the skirt is fitted.

The embodiment shown in FIGS. 3 and 4 is similar to that of FIG. 2, except that the strap, cord, wire or line 18 is dispensed with and a tuck 19 is provided in the bottom wall 16 which is maintained by stitching 20 or by any other suitable means for maintaining the tuck 19, such as by welding or by an adhesive or by metal staple or the like. The tuck 19 takes up excess material and serves to keep the tip portion taut. It also prevents the tip from being moved outside the sidewall of the segment. The tuck 19 may extend outwardly so as to be located below the bottom wall 16.

FIGS. 5 and 6 show an embodiment in which the bottom edges 15a of the walls 15 are formed by cutting the material forming the segment and then inserting a separate piece of material 21 which is then secured to the segment to form the bottom wall portion 16. The separate piece of material 21 may be formed of similar material to that of the segment or it may comprise a material having better wear-resistant properties. The securing together of the separate piece 21 and the remainder of the segment 12 may be carried out by stitching, welding or by an adhesive.

In the embodiment shown in FIG. 7, each side wall 15 is provided with a tuck 22 which is maintained by securing the two parts of the tuck 22 together. This has the effect of inwardly bending the bottom portion of the curved front wall portion 17 of the segment 12 to form the bottom wall portion 16 which, in use, lies at an angle to the horizontal which is less than that of the curved front wall 17 of the segment 12. The tuck 22 may extend outwardly or inwardly as shown.

We have found that by shaping the bottom of the segments 12 in the manner described, then as the device is moved on the gas cushion, the bottom regions of the segments 12 do not tend to be deflected sideways, but the segments remain stable and form an effective seal bewteen two adjacent segments along the whole of their height or depth. It will be appreciated that the flexible sealing skirt can be fixed to rigid structure of a hovercraft or lifting pad or to a loop of flexible material secured to the side of the rigid structure.

The material from which the segments 12 are formed may comprise a nylon or material sold under the registered trademark TERYLENE coated with a natural or synthetic rubber, e.g., noeprene or P.V.C. or polyurethane. The segments 12 may be moulded into the desired shape. Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such be employed.

We, therefore, particularly point out and distinctly claim as our invention:

1. A flexible segmented sealing skirt for use on apparatus which can be supported on a gas cushion, comprising a plurality of juxtaposed segments which in use are vertically extending and seal one against another, each segment being substantially U-shaped in horizontal transverse cross-section to provide a curved front wall and two side wall members, said side wall members having an upper end and a bottom end and each taper: ing from their upper end to their bottom end, the bottom end of each segment being provided with a bottom wall member which, when the skirt is in use, will selectively lie horizontally or at an angle to the horizontal which is less than the curved front wall of the segment.

2. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are connected together to form said bottom wall member.

3. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are connected together to form a bottom wall member integral with the segment.

4. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are interconnected by a bottom wall member secured thereto.

5. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are interconnected by a bottom wall member secured thereto, said bottom wall member having better wear resisting properties than the material from which the segment is formed.

6. A flexible segmented sealing skirt as claimed in claim 1, wherein a tensioning means is connected to said bottom wall.

7. A flexible segmented sealing skirt as claimed in claim 1, wherein a tensioning means is connected to said bottom wall, said tensioning means consisting of an elongate member.

8. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom end of the curved front wall of each segment is provided with a tuck to form said bottom wall member, means being provided to secure the parts of the tuck together.

9. A flexible segmented sealing skirt as claimed in claim 1, wherein each side wall member of each segment is provided with a tuck to lift the bottom end portion of said curved front wall to form said bottom wall member.

10. In combination an apparatus which can be supported on a gas cushion and a flexible segmented sealing skirt extending vertically downwardly from said apparatus, said skirt comprising a plurality of juxtaposed segments which in use are vertically extending and seal one against another, each segment being substantially U-shaped in horizontal transverse cross-section to provide a curved front wall and two side wall members, said side wall members having an upper end and a bottom end and each tapering from their upper end to their bottom end, the bottom end of each segment being provided with a bottom wall member which, when the skirt is in use, will selectively lie horizontally or at an angle to the horizontal which is less than the curved front wall of the segment. 

1. A flexible segmented sealing skirt for use on apparatus which can be supported on a gas cushion, comprising a plurality of juxtaposed segments which in use are vertically extending and seal one against another, each segment being substantially Ushaped in horizontal transverse cross-section to provide a curved front wall and two side wall members, said side wall members having an upper end and a bottom end and each tapering from their upper end to their bottom end, the bottom end of each segment being provided with a bottom wall member which, when the skirt is in use, will selectively lie horizontally or at an angle to the horizontal which is less than the curved front wall of the segment.
 2. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are connected together to form said bottom wall member.
 3. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are connected together to form a bottom wall member integral with the segment.
 4. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are interconnected by a bottom wall member secured thereto.
 5. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom edges of said two side wall members of each segment are interconnected by a bottom wall member secured thereto, said bottom wall member having better wear resisting properties than the material from which the segment is formed.
 6. A flexible segmented sealing skirt as claimed in claim 1, wherein a tensioning means is connected to said bottom wall.
 7. A flexible segmented sealing skirt as claimed in claim 1, wherein a tensioning means is connected to said bottom wall, said tensioning means consisting of an elongate member.
 8. A flexible segmented sealing skirt as claimed in claim 1, wherein the bottom end of the curved front wall of each segment is provided with a tuck to form said bottom wall member, means being provided to secure the parts of the tuck together.
 9. A flexible segmented sealing skirt as claimed in claim 1, wherein each side wall member of each segment is provided with a tuck to lift the bottom end portion of said curved front wall to form said bottom wall member.
 10. In combination an apparatus which can be supported on a gas cushion and a flexible segmented sealing skirt extending vertically downwardly from said apparatus, said skirt comprising a plurality of juxtaposed segments which in use are vertically extending and seal one against another, each segment being substantially U-shaped in horizontal transverse cross-section to provide a curved front wall and two side wall members, said side wall members having an upper end and a bottom end and each tapering from their upper end to their bottom end, the bottom end of each segment being provided with a bottom wall member which, when the skirt is in use, will selectively lie horizontally or at an angle to the horizontal which is less than the curved front wall of the segment. 